In this section, we describe the first demonstration of a soliton microcomb in a 4H-silicon carbide (SiC) microresonator. The CMOS-compatible fabrication process is described in [1]}, [2]}. SiC possesses a high linear and nonlinear refractive indices[2]} (\(n=2.6\)  and \(n_2=6.9\cdot 10^{-15}\)  cm2/W at 1550 nm), which makes it suitable for highly efficient, compact nonlinear photonic devices. However, the tight confinement and high material index of integrated waveguides make them susceptible to scattering losses caused by surface roughness. We demonstrate the fabrication of SiC microresonators with smooth sidewalls and strong confinement with record-high quality (Q) factors. The fabricated microring resonators have a radius of 100 µm, height of 500-600 nm, and width of 1850 nm.
